trim
open override fun trimClipStart(trackIndex: Int, clipId: Int, deltaSamples: Long, origin: MutationOrigin = MutationOrigin.User): Boolean
Moves the clip's start by deltaSamples while its content and its end stay where they are: positive cuts the beginning off, negative brings back what an earlier trim cut. Past the start of a MIDI clip's content, the content is shifted along so the new room is part of it; an audio clip cannot start before its source.